Hydraulic motor unit



Nov. 27,l 1945;

.DN NN J. B. VAN DER WERFF HYDRAULIC MTOR UNIT Original Filed June 25, 1942 7 filiaal/v Patented Nov. 27, 1945 HYDRAULIC MOTOR UNIT 'Jacob B. Van Der Werff, Pasadena, Calif., assignor to Adel Precision Products Corp., a corporation of California original application June 23, 1942, sex-ni No. 44s,ioz, now raient No. 2,359,949, amd october 10, 1944. Divided and this ary 8, 1944, Serial N0. 521,743

application Febru- 3 Claims. (Cl. Bil-54.6)

This invention relates to hydraulic remote control systems by means of which aircraft engine. throttles and other aircraft controls may be hydraulically operated and controlled, and more particularly relates to an improved hydraulic motor unit which is remotely controlled by' means of a master or pump unit. Y

This application is a division of my application for United States Letters Patent Ser. No.

448,102, 'led June 23, 1942, which issued as Patent No. 2,359,949 on Oct. 10, remote control system.

An object of the present invention is to provide an improved hydraulic motor unit such as described which will be positive and reliable of performance by reason of built-in valves and mechanism including hydraulic locking means which operates automatically upon. cessation of l1944, for Hydraulic -ow of operating uid thereto so that the airplane control or part operated by the unit is Y retained in. the desired position regardless of external forces.

Another object of my invention is to provide a motor unit such as described which is .provided with a novel means for communicating opposite -ends of the cylinder thereof through the piston therein, when said piston reaches the limitof its stroke in either direction thereby permitting passage of the fluid from one end of the cylinder to the other, thus making possible removal lof entrapped air and automatic synchronization of the motor unit with the aforesaid master or pump unit.

Another object of my invention is to provide a motor unit such as described which is provided plying operating uld to and returning fluid from'the motor unit, said ports opening into a bore 4 extending longitudinally through the body. Aportion of this bore between the ports 2 and 3 is reduced and forms a small cylinder bore 5 for a valve-actuating piston 6 which is shifted responsive to the delivery of uid under pressure through one or the other of the ports 2v and 3.

As here shown the ends of valve-actuating piston 6 'are adapted to abut the stems I of puppet valves 8 and 8 mounted in the bore '4l so as to control the flow of uid through cylinder passages IIl and II leading from opposite end portions of said bore into opposite ends of a cylinder l2 formed in the body member in spaced parallel l relation to the'bore l.

' Each of the .valves 8 and 9 is mounted in a tubular cage I3 screwed into an end of the bore I so as to be axially adjustable therein. Each cage has a valve seat I4 at its inner end, also a valve stem guide member I5. Springs I6 are` arranged to urge the valves 8 and 9 into seated position and to return the piston 6 to neutralposition in which both of the valves are closed.

with a means for relieving excessive pressures within the cylinder which may be caused by expansion of the fluid fects.

With the foregoing objects in view, together with such other objects and advantages asV may' subsequently appear, the invention resides in the therein due to thermal ef- Piston members Il are reciprocally mounted in the bores of the tubular cage I3 between the valves 8- and 9 .and 'adjustable-'screw plugs I8 i'n the outer ends of said cages. extended beyond the ends of the body I and are externally screw threaded for reception of lock nuts lI9 which abut the ends of the body I. Springs 20 are' arranged between the piston members Il and the plugs I8 to normally holdthe piston members' extended toward the valves 8 and 9. The valve springs I6 are mounted on the keepers 2l on the piston member II as shown in the left end of Fig. 1. This arrangement of the piston"members Ilprovides means which yieldingly'oppose fluid pressure in thermal expansion chambers in the bores of the valve cages I3 so that on thermal expansion of iluidin unit Y or uponexcessive pressure of this uid due to parts and in the combination, construction and 'i arrangementbf parts hereinafter described and' claimed, and illustrated by way ofexample in the accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view of a motor unit embodying my invention; y

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1.

Referring to the drawing more specifically, it is seen that a hydraulic motor unit made in accordance with this invention includes an elongated body I having ports Zand 3 providing for vconnection of fluid (not shown) for supthe excess pressure.

other causes the piston members I'I will be forced outwardly against theactions of the springs to enlarge said' chambers and relieve Upon contraction of the fluid in the unit, the pistons I1 be moved by the springs 28 to force uid vinto the cylin'- der I2.

Ports 22 the plugs I8 vent to the atmosphere the spaces between the plugs and piston members II to prevent formation of vacuum in said spaces and consequent inoperativeness of said pistons. The plugs I8 may be readily adjusted toprovideforchangingthetensionofthesprings The cages are thermal'expansion relief means associated therewith.

'I'he cages I3 are sealed at their inner ends by means of sealing rings 23, and at points adjacent said inner ends are formed with peripheral grooves 24 registering withv the cylinder passages I and II. The tubular valve stem guides I5 of the cages have portions of their bores of greater diameter than the portionsof the valve stems 1 therein so that radial ports I5' formed in said guides will provide for passage of huid into the bores of the members I5 and through the valve seats and the bores of the cages I3. Radial ports 25 in the cages aiord communication of the interior of the bores of the cages I3, through the grooves 24, with the passages I0 and II whereby when the valves 8 and 9 are opened iluid passages are provided from the ports 2 and 3 to the ends of cylinder I2.

The cylinder I2 is closed at its ends by mea of screw plugs 26 carrying suitably sealed and adjustable valve operating pins 21 for engaging and opening checkv valves 28 in the ends of a passage 29 extending through the motor piston 30 in said cylinder.

The check valves seat towards the outer ends oi the passage 29 and when the piston reaches a limit of its stroke in either direction one check valve 28 will be opened by one of the pins 21 while the other check valve 28 will be opened by pressure of the uid against it, thereby opening the passage 29 through the piston and providing for a synchronizing displacement aof fluid with respect to the end portions of the cylinder, as well as for removal of any trapped air in the motor unit.

Each of the pins 21 extends outwardly beyond the outer face of its associated plug 26 and is held in adjusted position by means of a nut 3I. A piston-like guide 32 is provided on each pin 21 and is-slidable in a counterbore 33 of the screw threaded opening 34 in which the pin is adjustable.

As here provided the motor piston 30 operates a drive means which includes a series of rack teeth 35 on the piston intermediate the piston ends which latter are provided with sealing rings 36. The teeth 35 mesh with pinion 31 keyed to a such devices and the motor piston. 'Ihis hydraulic locking action is effected upon cessation .of flow of fluid under pressure through either. of the intake ports 2 and 3, at which time the springs I6 operate to closethe valves 8 and 9 and at the same time move the piston 6 into neutral position in which no valve-opening force is applied thereby to said valves.

Both ends of the motor cylinder l2 are open to the expansion chambers in the inner end portions of the bores of the tubular cages I3 whereby when excessive pressure develops in either end of the cylinder -due tol thermal expansion or other causes, the pistons I1 are subject to movement to relieve the pressure. The springs 20 may be adjusted as hereinbefore noted to vary the setting of the pistons I1 so that theywill yield'to predetermined pressures'.

When uid under operating pressure is. delivered through the port 3, the valve actuating piston 5 ls moved to the left and against the valve stem of valve 8 and opens said valve while the pressure of the iluid opens valve 9. This allows operating fluid .to enterthe right end of cylinder I2 and move motor piston 30 to the left, the displaced fluid passing from theV left end of the cylinder through passage I0, past open valve 8 and out through the port 3; This operation of the motor piston causes movement of the shaft 38 in thel opposite direction to that which takes place when pressure fluid is delivered through the port 2.

It is now seen that the motor unit hereof is characterized by a particular construction, combination and relative arrangement of valves, fluid responsive actuating means, and associated parts and elements such that it will have greater reliability of performance and nicety of action and v control than similar devices heretofore used in the shaft 38 extending transversely through the body Operation When uid under pressure derived from a hydraulic system (not shown) is introduced through the intake port 2, the piston 6 is shifted to the right and opens the valve 9 while the pressure of said fluid is effective to open the valve 8, thereby applying pressure uid through the passage I0 into the left end of the cylinder I2 and causing the motor piston 30 to be shifted to the right. On this movementof the piston, the rack teeth 35 and pinion 31 drive the shaft 38 so that the device or mechanism .(not shown) and which is connected tothe shaft, will be operated. Fluid displaced by the motor piston 30 will ow through passage II, past open` valve 9 and .out through the port 3 into the hydraulic system (not shown) art, and at the same time be automatic as to thermal and other iluld displacement compensating actions as well as to its hydraulic locking action of its motor piston.

While I have shown and described a specific embodiment of my invention I dovnot limit myself to theexact details of construction set forth, and the invention embraces such changes, modifications and equivalents of the parts and their formation and arrangement as come within the Y purview of the appended claims.

1. A hydraulic motor unit subject to remote control, including a body member, a hydraulic cylinder associated with said body member, a reciprocable piston in said cylinder, a drive means responsive to movement of said piston and adapted for connection with an element or device to be controlled by said motor unit, said body member having ports adapted for connection with a source of operating uid and provided with passages leading from said ports to opposite ends of said cylinder, valves for controlling said passages arranged to be closed in the direction of the ow of return fluid from said cylinder and to be opened responsive to the pressure of the operating fluid whereby upon cessation of iiow of operating uid the piston lwill be hydraulically locked against movement, iluid responsive means movable in said body member for opening one oi' the valves simultaneously with the fluid effected opening of the other of said valves, fluid ex- Ipansion chambers in said unit connected with said passages at points between said valves and said cylinder, and means in said chambers yieldingly opposing the iluid pressures in them.

2. A hydraulic motor unit subject to remote control, including a bodymember, a hydraulic 3. In a hydraulic motor unit subject to remote control, a body member, a hydraulic cylinder associated with said body member, a reciprocable motor piston in said cylinder, said body member cylinder associated with said body member, a f

reciprocable piston in said cylinder, a drive means responsive to movement of said piston and adapted for connection with an element or device to be controlled by said motor unit, said body member having ports adapted for connection with a source of operating iiuid and provided with passages leading from said ports to opposite ends of said cylinder, valves for controlling. said ipassages arranged to be closedin the direction of the ilow of return fluid from said cylinder and to be opened responsive to the pressure of the operating iiuid whereby upon cessation of flow of operating fluid, the piston will be hydraulically locked against movement, uid responsive means movable in said body member for opening one oi' the valves simultaneously with the uid eected opening of the other of said valves; fluid expansion chambers in saidbody member connected with rsaid passages at points between the valves and the cylinder, and spring loaded pistons in said chambers arranged to be moved responsive cylinder and'passages.

having ports adapted for connection with a source of operating uid and provided with cylinderpassages leading from` said ports to opposite ends o! said cylinder, spring loaded valves controlling the flow ofl iiuid to and from said cylinder arranged in said passages to close in the. directipn o! the iiow of fluid from said cylinder and to open responsive to the pressure ot operating fluid owing into said passages toward said cylinder whereby upon cessation of flow of oper ating iiuid into either of said passages the motor piston will be hydraulically locked against movement in either direction, a bore in said body member having its ends open to said passages between said valves and said ports, a valve-actueating piston moving in said bore into a valveactuating position responsive to pressure of operating uid entering either of said passages, valve engaging means which on uid eiected movement of said valve-actuating piston will open one of said valves substantially simultaneously with the iluid eilected opening ofthe other of said valves, iluid expansion chambers coaxial with said valves and said bore and opening into said passages at points between said valves and said cylinder, and spring loaded pistons in said chambers larranged to move responsive to expansion and contraction of uid in said cylinders.

JACOB n'. vAN DER WERFF. 

